There are various methods of making micro and nanoporous materials from polymers. One method of making porous material is the Thermally Induced Phase Separation (TIPS) method. The general procedure for the TIPS process comprises the steps of: (1) forming a homogenous solution by melt blending the polymer with a high-boiling point, low molecular weight liquid or solid referred to as the diluent; (2) casting or extruding the solution into the desired shape; (3) cooling the solution to induce phase separation and solidification of polymer; (4) removing the diluent (most often by solvent extraction); and (5) evaporating the extractant to yield a porous structure. However, the TIPS method produces a very small fraction of nanopores, as most of the pores produced are micropores.
There remains a need to form nanoporous materials based on an organic material using a simple technique, such that few or no micropores are produced.